Analysis Of Ship Crash Performance Of Long-span Cable-stayed Bridges

To meet the increasing economic demand and improving transportation efficiency,long-span bridges have received more and more applications in practice.Cable-stayed bridges,with the merits of relatively low cost and design flexibility,are most widely adopted in bridges with the main span between 500 and 1000 meters.These bridges usually span over busy navigation channels,thus are subjected to high collision risk from passing vessels.As the matter of fact,many ship collision events have occurred recently.It is therefore imperative and necessary to study the behavior of long-span cable-stayed bridges subject to ship collisions.However,conducting a ship-collision experiment in laboratory is very expensive,and field testing is almost prohibitive.Therefore the numerical simulation might be the most convenient and economic research approach.This study will investigate the ship collision behavior of a 1018-m long main span cable-stayed bridge using LS-DYNA software.The main contents consist of the following parts:(1)The recent serious bridge impact accidents,research methodologies and relevant results in terms of ship collision are reviewed.(2)The basic theories and key technologies in numerical simulation of ship-bridge collision are reviewed.The K&C constitutive model for concrete is introduced and the parameters in the model are calibrated using existing experimental results.(3)A numerical model is developed to simulate the laboratory tests of a scaled circular reinforced concrete pier under a pendulum impact.The numerical results are compared with the experimental ones to verify the effectiveness and accuracy of the numerical model adopted.(4)The finite element models of the whole bridge and ship are established.Several loading cases are calculated and the results are compared with those using simplified models.The comparison provides a reference for the engineering applications of the simplified simulations and experiments.(5)The effects of ship mass,impact velocity,impact angle and impact position on the impact force,global responses of the bridge,and bridge damage are studied.A fast estimate of the ship impact force is proposed.(6)A new float anti-collision system is proposed.The suggestions regarding the design and optimization of the protective system are provided.The study does not only provide references of anti-collision design for long-span cable-stayed bridges,but also assists the inspection and strengthening after the collision occurs.It will reduce the economic loss and social impact of the catastrophe of ship-bridge collisions.